172 citations · 1.1k across the 34 of their papers we have counts for
35 papers
Mirror Symmetry and Double Signature Change
Tevian Dray, Charles Hellaby
The black mirror spacetime proposed by Tzanavaris, Boyle, and Turok [1] connects the two exterior regions of the extended Schwarzschild black hole directly to each other, with no i…
Rotation, Embedding and Topology for the Szekeres Geometry
Charles Hellaby, Robert G. Buckley
Recent work on the Szekeres inhomogeneous cosmological models uncovered a surprising rotation effect. Hellaby showed that the angular coordinates do not have a constant or…
Reversing the Null Limit of the Szekeres Metric
Charles Hellaby, Otakar Svítek
The null limits of the Lemaitre-Tolman and Szekeres spacetimes are known to be the Vaidya and news-free Robinson-Trautman metrics. We generalise this result to the case of non-zero…
Calculating Observables in Inhomogeneous Cosmologies I: General Framework
Charles Hellaby, Anthony Walters
We lay out a general framework for calculating the variation of a set of cosmological observables, down the past null cone of an arbitrarily placed observer, in a given arbitrary i…
Frame Rotation in the Szekeres Spacetimes
Charles Hellaby
The Szekeres metric is an inhomogeneous cosmological model without any symmetries. The standard Riemann-type coordinates can be transformed into spherical-type coordinates, but the…
Symmetry and Equivalence in Szekeres Models
Ira Georg, Charles Hellaby
We solve for all Szekeres metrics that have a single Killing vector. For quasi hyperboloidal () metrics, we find that translational symmetries are possible, but only in metr…